Address c_if, Permutation, and transpile parameter deprecations…

… in Qiskit 1.3 (#1482)

* `Permutation` instances in tomography experiments have been replaced
with `PermutationGate` instances that work the same way for those
experiments. The only user facing change should be the avoidance of
deprecation warnings in Qiskit 1.3.
* `c_if` usage on conditional gates in some tests has been replaced with
`if_test` blocks around those gates.
* `ParallelExperiment` now considers a `target` transpiler option when
determining how large a circuit to make when combining subexperiments
into a larger circuit. Previously it considered the number of qubits in
a `coupling_map` transpiler option or in the experiment's backend.
* Use of `instruction_durations` as a transpile option was replaced with
`target` in one test (`instruction_durations` was deprecated as a
transpiler parameter).
* Add explicit `order="F"` argument to `cvxpy.vec()` calls. This
function started issuing a `FutureWarning` in the latest version of
cvxpy about the default order changing from F to C.

qiskit_experiments/framework/composite/parallel_experiment.py

@@ -89,14 +89,23 @@ def _combined_circuits(self, device_layout: bool) -> List[QuantumCircuit]:
             # Num qubits will be computed from sub experiments
             num_qubits = len(self.physical_qubits)
         else:
-            # Work around for backend coupling map circuit inflation
+            # Expand the number of qubits similar to how qiskit.transpile does
+            # Here we progress from most to least specific way of specifying
+            # the number of qubits: coupling_map->target->backend
+            #
+            # TODO: Behave more like a layout transpiler pass and set the
+            # _layout property on the circuits. Doing this requires accessing
+            # private attributes of Qiskit or possibly running a layout pass of
+            # the transpiler if that can be done without too much overhead.
+            num_qubits = 1 + max(self.physical_qubits)
             coupling_map = getattr(self.transpile_options, "coupling_map", None)
-            if coupling_map is None and self.backend:
-                coupling_map = self._backend_data.coupling_map
+            target = getattr(self.transpile_options, "target", None)
             if coupling_map is not None:
-                num_qubits = 1 + max(*self.physical_qubits, np.max(coupling_map))
-            else:
-                num_qubits = 1 + max(self.physical_qubits)
+                num_qubits = max(num_qubits, 1 + np.max(coupling_map))
+            elif target is not None:
+                num_qubits = max(num_qubits, target.num_qubits)
+            elif self.backend:
+                num_qubits = max(num_qubits, self._backend_data.num_qubits)
 
         joint_circuits = []
         sub_qubits = 0

qiskit_experiments/library/tomography/fitters/cvxpy_lstsq.py

@@ -300,8 +300,8 @@ def cvxpy_linear_lstsq(
             idx = 0
             for i in range(num_circ_components):
                 for j in range(num_tomo_components):
-                    model = bms_r[idx] @ cvxpy.vec(rhos_r[idx]) - bms_i[idx] @ cvxpy.vec(
-                        rhos_i[idx]
+                    model = bms_r[idx] @ cvxpy.vec(rhos_r[idx], order="F") - bms_i[idx] @ cvxpy.vec(
+                        rhos_i[idx], order="F"
                     )
                     data = probability_data[i, j]
                     args.append(model - data)

qiskit_experiments/library/tomography/fitters/cvxpy_utils.py

@@ -234,8 +234,8 @@ def partial_trace_constaint(
     ptr = partial_trace_super(input_dim, output_dim)
     vec_cons = np.ravel(constraint, order="F")
     return [
-        ptr @ cvxpy.vec(mat_r) == vec_cons.real.round(12),
-        ptr @ cvxpy.vec(mat_i) == vec_cons.imag.round(12),
+        ptr @ cvxpy.vec(mat_r, order="F") == vec_cons.real.round(12),
+        ptr @ cvxpy.vec(mat_i, order="F") == vec_cons.imag.round(12),
     ]
 
 
@@ -274,7 +274,7 @@ def trace_preserving_constaint(
     output_dim = sdim // input_dim
 
     ptr = partial_trace_super(input_dim, output_dim)
-    cons = [ptr @ cvxpy.vec(arg_r) == np.identity(input_dim).ravel()]
+    cons = [ptr @ cvxpy.vec(arg_r, order="F") == np.identity(input_dim).ravel()]
 
     if hermitian:
         return cons
@@ -286,7 +286,7 @@ def trace_preserving_constaint(
         arg_i = mat_i
     else:
         raise TypeError("Input must be a cvxpy variable or list of variables")
-    cons.append(ptr @ cvxpy.vec(arg_i) == np.zeros(input_dim**2))
+    cons.append(ptr @ cvxpy.vec(arg_i, order="F") == np.zeros(input_dim**2))
     return cons
 
 

qiskit_experiments/library/tomography/tomography_experiment.py

@@ -16,7 +16,7 @@
 from typing import Union, Optional, Iterable, List, Tuple, Sequence
 from itertools import product
 from qiskit.circuit import QuantumCircuit, Instruction, ClassicalRegister, Clbit
-from qiskit.circuit.library import Permutation
+from qiskit.circuit.library import PermutationGate
 from qiskit.providers.backend import Backend
 from qiskit.quantum_info.operators.base_operator import BaseOperator
 
@@ -278,7 +278,7 @@ def _permute_circuit(self) -> QuantumCircuit:
             prep_qargs = list(self._prep_indices)
             if len(self._prep_indices) != total_qubits:
                 prep_qargs += [i for i in range(total_qubits) if i not in self._prep_indices]
-            perm_circ.append(Permutation(total_qubits, prep_qargs).inverse(), range(total_qubits))
+            perm_circ.append(PermutationGate(prep_qargs).inverse(), range(total_qubits))
 
         # Apply original circuit
         if total_clbits:
@@ -291,6 +291,6 @@ def _permute_circuit(self) -> QuantumCircuit:
             meas_qargs = list(self._meas_indices)
             if len(self._meas_indices) != total_qubits:
                 meas_qargs += [i for i in range(total_qubits) if i not in self._meas_indices]
-            perm_circ.append(Permutation(total_qubits, meas_qargs), range(total_qubits))
+            perm_circ.append(PermutationGate(meas_qargs), range(total_qubits))
 
         return perm_circ

releasenotes/notes/qiskit13-deprecations-afece0ceea29f3f7.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    Minor adjustments were made to Qiskit Experiments internals to avoid
+    deprecation warnings when using Qiskit 1.3. See `#1482
+    <https://github.com/qiskit-community/qiskit-experiments/pull/1482>_`.

test/library/characterization/test_t1.py

@@ -15,7 +15,10 @@
 
 from test.base import QiskitExperimentsTestCase
 import numpy as np
+from qiskit.circuit import Delay, Parameter
+from qiskit.circuit.library import CXGate, Measure, RXGate
 from qiskit.qobj.utils import MeasLevel
+from qiskit.transpiler import InstructionProperties, Target
 from qiskit_ibm_runtime.fake_provider import FakeAthensV2
 from qiskit_experiments.test.noisy_delay_aer_simulator import NoisyDelayAerBackend
 from qiskit_experiments.framework import ExperimentData, ParallelExperiment
@@ -249,22 +252,33 @@ def test_t1_low_quality(self):
     def test_t1_parallel_exp_transpile(self):
         """Test parallel transpile options for T1 experiment"""
         num_qubits = 5
-        instruction_durations = []
-        for i in range(num_qubits):
-            instruction_durations += [
-                ("rx", [i], (i + 1) * 10, "ns"),
-                ("measure", [i], (i + 1) * 1000, "ns"),
-            ]
-        coupling_map = [[i - 1, i] for i in range(1, num_qubits)]
-        basis_gates = ["rx", "delay"]
+        target = Target(num_qubits=num_qubits)
+        target.add_instruction(
+            RXGate(Parameter("t")),
+            properties={
+                (i,): InstructionProperties(duration=(i + 1) * 10e-9) for i in range(num_qubits)
+            },
+        )
+        target.add_instruction(
+            Measure(),
+            properties={
+                (i,): InstructionProperties(duration=(i + 1) * 1e-6) for i in range(num_qubits)
+            },
+        )
+        target.add_instruction(
+            Delay(Parameter("t")),
+            properties={(i,): None for i in range(num_qubits)},
+        )
+        target.add_instruction(
+            CXGate(),
+            properties={(i - 1, i): None for i in range(1, num_qubits)},
+        )
 
         exp1 = T1([1], delays=[50e-9, 100e-9, 160e-9])
         exp2 = T1([3], delays=[40e-9, 80e-9, 190e-9])
         parexp = ParallelExperiment([exp1, exp2], flatten_results=False)
         parexp.set_transpile_options(
-            basis_gates=basis_gates,
-            instruction_durations=instruction_durations,
-            coupling_map=coupling_map,
+            target=target,
             scheduling_method="alap",
         )
 

test/library/tomography/tomo_utils.py

@@ -52,8 +52,10 @@ def teleport_circuit(flatten_creg=True):
     teleport.measure(0, creg[0])
     teleport.measure(1, creg[1])
     # Conditionals
-    teleport.z(2).c_if(creg[0], 1)
-    teleport.x(2).c_if(creg[1], 1)
+    with teleport.if_test((creg[0], True)):
+        teleport.z(2)
+    with teleport.if_test((creg[1], True)):
+        teleport.x(2)
     return teleport
 
 
@@ -76,8 +78,10 @@ def teleport_bell_circuit(flatten_creg=True):
     teleport.h(0)
     teleport.measure(0, creg[0])
     teleport.measure(1, creg[1])
-    teleport.z(2).c_if(creg[0], 1)
-    teleport.x(2).c_if(creg[1], 1)
+    with teleport.if_test((creg[0], True)):
+        teleport.z(2)
+    with teleport.if_test((creg[1], True)):
+        teleport.x(2)
     return teleport